Is the Pariah dog Dogmeat? Because when I found him, there was totally a corpse that had blue torn clothing, and I'm pretty sure it was part of the Vault Suit sprite.
So, maybe after the Lone Wanderer got kicked out of the vault, his dog was like, I'M SUPER HIGH LEVEL! I HAVE 750 HP! I'M KILLIN' DEATH CLAWS AND GECKOS AND EVERYTHIIIIING! and then killed the Vault Dweller, by accident or because he turned crazy.
Is there any information on this?
I'm probably totally wrong. Maybe it's in the Fallout bible, but I'm too chicken to read too much of it in case I get spoiled (I'm not done FO2 yet! I just found the dog myself).